Field of the Invention
The present invention is involved with an electrically operated valve, and relates to an electrically operated valve, for example, used in a heat pump type heating and cooling system.
Description of the Conventional Art
Conventionally, there has been advanced development of an electrically operated valve which aims at downsizing, achieving great capacity and saving energy. As one example of the conventional electrically operated valve as mentioned above, patent document 1 discloses a technique which can use a valve opening spring having a smaller spring load by making force acting in a valve closing direction as small as possible.
The electrically operated valve disclosed in the patent document 1 is provided with a valve main body having a valve chamber, a first inlet and outlet which is open to the valve chamber and is transversely situated, a valve port with valve seat which is open to the valve chamber and is vertically situated, and a second inlet and outlet which is communicated with the valve port, a valve body which is arranged in the valve chamber in an up-and-down movable manner so as to open and close the valve port, an elevation drive means which has an electric motor for moving up and down the valve body, and a valve opening spring which energizes the valve body in a valve opening direction, a bore diameter of the valve port is set to be approximately identical to a chamber diameter of a back pressure chamber which is defined above the valve body, a pressure equalizing passage is provided within the valve body, the pressure equalizing passage having an opening lower end surface so as to communicate the valve port with the back pressure chamber, and dimensions of the respective portions are set so that a value obtained by dividing a lower end opening area of the pressure equalizing passage by an area of the valve port is within a predetermined range.
In this kind of electrically operated valve, a fluid (a refrigerant) is flowed in two directions including a first flowing direction in which the refrigerant heads for the second inlet and outlet from the first inlet and outlet, and a second flowing direction in which the refrigerant heads for the first inlet and outlet from the second inlet and outlet, however, for example, in the case that a refrigerant (a gas refrigerant) constructed by gas is flowed in the first flowing direction in an excessive gas state, there has been a problem that a periodic eddy flow is generated in the vicinity of an area between right and left portions of the valve port and an inner wall surface of the valve main body in the case that the valve chamber is seen from the first inlet and outlet side, and an abnormal noise is generated with the periodic eddy flow. Further, for example, in the case that the gas refrigerant is flowed in the second flowing direction in the excessive gas state, there has been a problem that the periodic eddy flow is generated in the vicinity of an area between a portion in an opposite side to the first inlet and outlet in the valve port and the inner wall surface of the valve main body, and the abnormal noise is generated with the periodic eddy flow (refer to FIG. 7). Specifically, for example, in the case that the gas refrigerant is flowed in the first flowing direction in the excessive gas state, the periodic eddy flow mentioned above is generated at a high differential pressure and an extremely small valve opening degree. This matter has been confirmed by experiments executed by the inventors of the present invention (refer to FIG. 8).
There has been conventionally fear that the abnormal noise at the using time as mentioned above has been generated in various valve devices, and patent documents 2 and 3 disclose prior arts which inhibit the abnormal noise from being generated in an expansion valve and a dry valve which are used in a refrigeration cycle.
The expansion valve disclosed in the patent document 2 is an expansion valve having a main body which is provided with an opening in a side surface and a lower surface and has a space in an inner portion, a valve body and a valve seat which form a throttle portion in the inner portion of the main body, a shaft which is connected to the valve body and has a rotor in an upper portion, a case which surrounds the shaft and the rotor, a stator which is positioned in an outer periphery of the rotor, a supporting means which supports the main body and the shaft, a first pipe which is connected to the opening in the side surface of the main body and a second pipe which is connected to the opening of the lower surface of the main body, wherein the expansion valve is provided with a rectifying means which is positioned in the inner portion of the main body, has one end fixed to the main body and the other end fixed to the supporting means, has a plurality of through holes in a side surface and is formed into a hollow shape.
Further, the dry-type valve disclosed in the patent document 3 is provided in a peripheral side of a valve seat with a passage which communicates a valve chamber and a valve outlet in a valve closing state, a throttle constructed by a porous body is arranged in the passage, an elastic body coming into contact with the porous body in the valve closing state is provided in a valve rod side of the dry valve, the elastic body is functioned as a valve body, and the porous body is functioned as the valve seat.